Installation switching devices may, for example, be circuit breakers, residual current devices, motor protection switches or selective main-line circuit breakers.
One circuit breaker of this type is disclosed, for example, in DE 10 2008 006 863 A1. In a circuit breaker such as this, a short-circuit current is disconnected with the aid of an impact-type armature. The field of a magnet coil through which current flows excites the magnetic circuit within the electromagnetic short-circuit current release, and the impact-type armature is thus moved by electrodynamic interaction. A striking pin is coupled to the impact-type armature and strikes the contact lever, as a result of which the contact point is opened, and the striking pin at the same time acts on the switching mechanism, which leads to unlatching of the switching mechanism and therefore to the contact point being kept open permanently until the switching mechanism is latched again and the contact point can only then be closed again.
In known installation switching devices, overcurrent tripping takes place with the aid of a thermomechanical tripping element, generally a thermal bimetallic strip. The overcurrent heats the thermal bimetallic strip, resulting in its bending. In the bent state, the thermal bimetallic strip unlatches the switching mechanism via an appropriate link by means of a switching mechanism operating element, in response to which the contact point is likewise permanently opened until the switching mechanism is latched again and the contact point can only then be closed again.
In a circuit breaker, the contact lever is generally in the form of a single-armed or two-armed lever which is mounted on a shaft such that it can pivot. The moving contact piece is attached to one of the free ends of the lever. In a motor protection switch, a double contact link is used as a contact lever. The double contact link is mounted such that it can move and is fitted at each of its two free ends with a moving contact piece. The two moving contact pieces interact with a respective stationary contact piece thus forming two contact points and allowing the switching power to be distributed between two contact points, as a result of which each individual contact point is less severely loaded when short-circuit disconnection takes place.
However, in known installation switching devices, the response rate of the magnetic release is limited since it includes a plurality of mechanical subsystems, each of which has a certain amount of mechanical inertia. The current limiting in the event of a short circuit is therefore also limited.